1 /* 2 * Copyright (c) 1983, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD$ 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94"; 38 #endif /* LIBC_SCCS and not lint */ 39 40 #include <sys/param.h> 41 #include <sys/socket.h> 42 #include <sys/stat.h> 43 44 #include <netinet/in.h> 45 #include <arpa/inet.h> 46 47 #include <signal.h> 48 #include <fcntl.h> 49 #include <netdb.h> 50 #include <unistd.h> 51 #include <pwd.h> 52 #include <errno.h> 53 #include <stdio.h> 54 #include <ctype.h> 55 #include <string.h> 56 #ifdef YP 57 #include <rpc/rpc.h> 58 #include <rpcsvc/yp_prot.h> 59 #include <rpcsvc/ypclnt.h> 60 #endif 61 62 /* wrapper for KAME-special getnameinfo() */ 63 #ifndef NI_WITHSCOPEID 64 #define NI_WITHSCOPEID 0 65 #endif 66 67 extern int innetgr __P(( const char *, const char *, const char *, const char * )); 68 69 #define max(a, b) ((a > b) ? a : b) 70 71 int __ivaliduser __P((FILE *, u_int32_t, const char *, const char *)); 72 static int __icheckhost __P((void *, char *, int, int)); 73 74 char paddr[INET6_ADDRSTRLEN]; 75 76 int 77 rcmd(ahost, rport, locuser, remuser, cmd, fd2p) 78 char **ahost; 79 u_short rport; 80 const char *locuser, *remuser, *cmd; 81 int *fd2p; 82 { 83 struct addrinfo hints, *res, *ai; 84 struct sockaddr_storage from; 85 fd_set reads; 86 long oldmask; 87 pid_t pid; 88 int s, aport, lport, timo, error; 89 char c; 90 int refused; 91 char num[8]; 92 93 pid = getpid(); 94 95 memset(&hints, 0, sizeof(hints)); 96 hints.ai_flags = AI_CANONNAME; 97 hints.ai_family = AF_UNSPEC; 98 hints.ai_socktype = SOCK_STREAM; 99 hints.ai_protocol = 0; 100 (void)snprintf(num, sizeof(num), "%d", ntohs(rport)); 101 error = getaddrinfo(*ahost, num, &hints, &res); 102 if (error) { 103 fprintf(stderr, "rcmd: getaddrinfo: %s\n", 104 gai_strerror(error)); 105 if (error == EAI_SYSTEM) 106 fprintf(stderr, "rcmd: getaddrinfo: %s\n", 107 strerror(errno)); 108 return (-1); 109 } 110 if (res->ai_canonname) 111 *ahost = res->ai_canonname; 112 ai = res; 113 refused = 0; 114 oldmask = sigblock(sigmask(SIGURG)); 115 for (timo = 1, lport = IPPORT_RESERVED - 1;;) { 116 s = rresvport_af(&lport, ai->ai_family); 117 if (s < 0) { 118 if (errno == EAGAIN) 119 (void)fprintf(stderr, 120 "rcmd: socket: All ports in use\n"); 121 else 122 (void)fprintf(stderr, "rcmd: socket: %s\n", 123 strerror(errno)); 124 sigsetmask(oldmask); 125 freeaddrinfo(res); 126 return (-1); 127 } 128 _libc_fcntl(s, F_SETOWN, pid); 129 if (connect(s, ai->ai_addr, ai->ai_addrlen) >= 0) 130 break; 131 (void)_libc_close(s); 132 if (errno == EADDRINUSE) { 133 lport--; 134 continue; 135 } 136 if (errno == ECONNREFUSED) 137 refused = 1; 138 if (ai->ai_next != NULL) { 139 int oerrno = errno; 140 141 getnameinfo(ai->ai_addr, ai->ai_addrlen, 142 paddr, sizeof(paddr), 143 NULL, 0, 144 NI_NUMERICHOST|NI_WITHSCOPEID); 145 (void)fprintf(stderr, "connect to address %s: ", 146 paddr); 147 errno = oerrno; 148 perror(0); 149 ai = ai->ai_next; 150 getnameinfo(ai->ai_addr, ai->ai_addrlen, 151 paddr, sizeof(paddr), 152 NULL, 0, 153 NI_NUMERICHOST|NI_WITHSCOPEID); 154 fprintf(stderr, "Trying %s...\n", paddr); 155 continue; 156 } 157 if (refused && timo <= 16) { 158 (void)_libc_sleep(timo); 159 timo *= 2; 160 ai = res; 161 refused = 0; 162 continue; 163 } 164 freeaddrinfo(res); 165 (void)fprintf(stderr, "%s: %s\n", *ahost, strerror(errno)); 166 sigsetmask(oldmask); 167 return (-1); 168 } 169 lport--; 170 if (fd2p == 0) { 171 _libc_write(s, "", 1); 172 lport = 0; 173 } else { 174 char num[8]; 175 int s2 = rresvport_af(&lport, ai->ai_family), s3; 176 int len = ai->ai_addrlen; 177 int nfds; 178 179 if (s2 < 0) 180 goto bad; 181 listen(s2, 1); 182 (void)snprintf(num, sizeof(num), "%d", lport); 183 if (_libc_write(s, num, strlen(num)+1) != strlen(num)+1) { 184 (void)fprintf(stderr, 185 "rcmd: write (setting up stderr): %s\n", 186 strerror(errno)); 187 (void)_libc_close(s2); 188 goto bad; 189 } 190 nfds = max(s, s2)+1; 191 if(nfds > FD_SETSIZE) { 192 fprintf(stderr, "rcmd: too many files\n"); 193 (void)_libc_close(s2); 194 goto bad; 195 } 196 again: 197 FD_ZERO(&reads); 198 FD_SET(s, &reads); 199 FD_SET(s2, &reads); 200 errno = 0; 201 if (select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){ 202 if (errno != 0) 203 (void)fprintf(stderr, 204 "rcmd: select (setting up stderr): %s\n", 205 strerror(errno)); 206 else 207 (void)fprintf(stderr, 208 "select: protocol failure in circuit setup\n"); 209 (void)_libc_close(s2); 210 goto bad; 211 } 212 s3 = accept(s2, (struct sockaddr *)&from, &len); 213 switch (from.ss_family) { 214 case AF_INET: 215 aport = ntohs(((struct sockaddr_in *)&from)->sin_port); 216 break; 217 #ifdef INET6 218 case AF_INET6: 219 aport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port); 220 break; 221 #endif 222 default: 223 aport = 0; /* error */ 224 break; 225 } 226 /* 227 * XXX careful for ftp bounce attacks. If discovered, shut them 228 * down and check for the real auxiliary channel to connect. 229 */ 230 if (aport == 20) { 231 _libc_close(s3); 232 goto again; 233 } 234 (void)_libc_close(s2); 235 if (s3 < 0) { 236 (void)fprintf(stderr, 237 "rcmd: accept: %s\n", strerror(errno)); 238 lport = 0; 239 goto bad; 240 } 241 *fd2p = s3; 242 if (aport >= IPPORT_RESERVED || aport < IPPORT_RESERVED / 2) { 243 (void)fprintf(stderr, 244 "socket: protocol failure in circuit setup.\n"); 245 goto bad2; 246 } 247 } 248 (void)_libc_write(s, locuser, strlen(locuser)+1); 249 (void)_libc_write(s, remuser, strlen(remuser)+1); 250 (void)_libc_write(s, cmd, strlen(cmd)+1); 251 if (_libc_read(s, &c, 1) != 1) { 252 (void)fprintf(stderr, 253 "rcmd: %s: %s\n", *ahost, strerror(errno)); 254 goto bad2; 255 } 256 if (c != 0) { 257 while (_libc_read(s, &c, 1) == 1) { 258 (void)_libc_write(STDERR_FILENO, &c, 1); 259 if (c == '\n') 260 break; 261 } 262 goto bad2; 263 } 264 sigsetmask(oldmask); 265 freeaddrinfo(res); 266 return (s); 267 bad2: 268 if (lport) 269 (void)_libc_close(*fd2p); 270 bad: 271 (void)_libc_close(s); 272 sigsetmask(oldmask); 273 freeaddrinfo(res); 274 return (-1); 275 } 276 277 int 278 rresvport(port) 279 int *port; 280 { 281 return rresvport_af(port, AF_INET); 282 } 283 284 int 285 rresvport_af(alport, family) 286 int *alport, family; 287 { 288 int i, s, len, err; 289 struct sockaddr_storage ss; 290 u_short *sport; 291 292 memset(&ss, 0, sizeof(ss)); 293 ss.ss_family = family; 294 switch (family) { 295 case AF_INET: 296 ((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in); 297 sport = &((struct sockaddr_in *)&ss)->sin_port; 298 ((struct sockaddr_in *)&ss)->sin_addr.s_addr = INADDR_ANY; 299 break; 300 #ifdef INET6 301 case AF_INET6: 302 ((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in6); 303 sport = &((struct sockaddr_in6 *)&ss)->sin6_port; 304 ((struct sockaddr_in6 *)&ss)->sin6_addr = in6addr_any; 305 break; 306 #endif 307 default: 308 errno = EAFNOSUPPORT; 309 return -1; 310 } 311 312 s = socket(ss.ss_family, SOCK_STREAM, 0); 313 if (s < 0) 314 return (-1); 315 #if 0 /* compat_exact_traditional_rresvport_semantics */ 316 sin.sin_port = htons((u_short)*alport); 317 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0) 318 return (s); 319 if (errno != EADDRINUSE) { 320 (void)_libc_close(s); 321 return (-1); 322 } 323 #endif 324 *sport = 0; 325 if (bindresvport2(s, (struct sockaddr *)&ss, 326 ((struct sockaddr *)&ss)->sa_len) == -1) { 327 (void)_libc_close(s); 328 return (-1); 329 } 330 *alport = (int)ntohs(*sport); 331 return (s); 332 } 333 334 int __check_rhosts_file = 1; 335 char *__rcmd_errstr; 336 337 int 338 ruserok(rhost, superuser, ruser, luser) 339 const char *rhost, *ruser, *luser; 340 int superuser; 341 { 342 return ruserok_af(rhost, superuser, ruser, luser, AF_INET); 343 } 344 345 int 346 ruserok_af(rhost, superuser, ruser, luser, af) 347 const char *rhost, *ruser, *luser; 348 int superuser, af; 349 { 350 struct hostent *hp; 351 union { 352 struct in_addr addr_in; 353 struct in6_addr addr_in6; 354 } addr; 355 char **ap; 356 int ret, h_error; 357 358 if ((hp = getipnodebyname(rhost, af, AI_DEFAULT, &h_error)) == NULL) 359 return (-1); 360 ret = -1; 361 for (ap = hp->h_addr_list; *ap; ++ap) { 362 bcopy(*ap, &addr, hp->h_length); 363 if (iruserok_af(&addr, superuser, ruser, luser, af) == 0) { 364 ret = 0; 365 break; 366 } 367 } 368 freehostent(hp); 369 return (ret); 370 } 371 372 /* 373 * New .rhosts strategy: We are passed an ip address. We spin through 374 * hosts.equiv and .rhosts looking for a match. When the .rhosts only 375 * has ip addresses, we don't have to trust a nameserver. When it 376 * contains hostnames, we spin through the list of addresses the nameserver 377 * gives us and look for a match. 378 * 379 * Returns 0 if ok, -1 if not ok. 380 */ 381 int 382 iruserok(raddr, superuser, ruser, luser) 383 unsigned long raddr; 384 int superuser; 385 const char *ruser, *luser; 386 { 387 return iruserok_af(&raddr, superuser, ruser, luser, AF_INET); 388 } 389 390 int 391 iruserok_af(raddr, superuser, ruser, luser, af) 392 void *raddr; 393 int superuser; 394 const char *ruser, *luser; 395 int af; 396 { 397 register char *cp; 398 struct stat sbuf; 399 struct passwd *pwd; 400 FILE *hostf; 401 uid_t uid; 402 int first; 403 char pbuf[MAXPATHLEN]; 404 int len = 0; 405 406 switch (af) { 407 case AF_INET: 408 len = sizeof(struct in_addr); 409 break; 410 #ifdef INET6 411 case AF_INET6: 412 len = sizeof(struct in6_addr); 413 break; 414 #endif 415 } 416 417 first = 1; 418 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r"); 419 again: 420 if (hostf) { 421 if (__ivaliduser_af(hostf, raddr, luser, ruser, af, len) 422 == 0) { 423 (void)fclose(hostf); 424 return (0); 425 } 426 (void)fclose(hostf); 427 } 428 if (first == 1 && (__check_rhosts_file || superuser)) { 429 first = 0; 430 if ((pwd = getpwnam(luser)) == NULL) 431 return (-1); 432 (void)strcpy(pbuf, pwd->pw_dir); 433 (void)strcat(pbuf, "/.rhosts"); 434 435 /* 436 * Change effective uid while opening .rhosts. If root and 437 * reading an NFS mounted file system, can't read files that 438 * are protected read/write owner only. 439 */ 440 uid = geteuid(); 441 (void)seteuid(pwd->pw_uid); 442 hostf = fopen(pbuf, "r"); 443 (void)seteuid(uid); 444 445 if (hostf == NULL) 446 return (-1); 447 /* 448 * If not a regular file, or is owned by someone other than 449 * user or root or if writeable by anyone but the owner, quit. 450 */ 451 cp = NULL; 452 if (lstat(pbuf, &sbuf) < 0) 453 cp = ".rhosts lstat failed"; 454 else if (!S_ISREG(sbuf.st_mode)) 455 cp = ".rhosts not regular file"; 456 else if (fstat(fileno(hostf), &sbuf) < 0) 457 cp = ".rhosts fstat failed"; 458 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid) 459 cp = "bad .rhosts owner"; 460 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH)) 461 cp = ".rhosts writeable by other than owner"; 462 /* If there were any problems, quit. */ 463 if (cp) { 464 __rcmd_errstr = cp; 465 (void)fclose(hostf); 466 return (-1); 467 } 468 goto again; 469 } 470 return (-1); 471 } 472 473 /* 474 * XXX 475 * Don't make static, used by lpd(8). 476 * 477 * Returns 0 if ok, -1 if not ok. 478 */ 479 int 480 __ivaliduser(hostf, raddr, luser, ruser) 481 FILE *hostf; 482 u_int32_t raddr; 483 const char *luser, *ruser; 484 { 485 return __ivaliduser_af(hostf, &raddr, luser, ruser, AF_INET, 486 sizeof(raddr)); 487 } 488 489 int 490 __ivaliduser_af(hostf, raddr, luser, ruser, af, len) 491 FILE *hostf; 492 void *raddr; 493 const char *luser, *ruser; 494 int af, len; 495 { 496 register char *user, *p; 497 int ch; 498 char buf[MAXHOSTNAMELEN + 128]; /* host + login */ 499 char hname[MAXHOSTNAMELEN]; 500 struct hostent *hp; 501 /* Presumed guilty until proven innocent. */ 502 int userok = 0, hostok = 0; 503 int h_error; 504 #ifdef YP 505 char *ypdomain; 506 507 if (yp_get_default_domain(&ypdomain)) 508 ypdomain = NULL; 509 #else 510 #define ypdomain NULL 511 #endif 512 /* We need to get the damn hostname back for netgroup matching. */ 513 if ((hp = getipnodebyaddr((char *)raddr, len, af, &h_error)) == NULL) 514 return (-1); 515 strncpy(hname, hp->h_name, sizeof(hname)); 516 hname[sizeof(hname) - 1] = '\0'; 517 freehostent(hp); 518 519 while (fgets(buf, sizeof(buf), hostf)) { 520 p = buf; 521 /* Skip lines that are too long. */ 522 if (strchr(p, '\n') == NULL) { 523 while ((ch = getc(hostf)) != '\n' && ch != EOF); 524 continue; 525 } 526 if (*p == '\n' || *p == '#') { 527 /* comment... */ 528 continue; 529 } 530 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') { 531 *p = isupper((unsigned char)*p) ? tolower((unsigned char)*p) : *p; 532 p++; 533 } 534 if (*p == ' ' || *p == '\t') { 535 *p++ = '\0'; 536 while (*p == ' ' || *p == '\t') 537 p++; 538 user = p; 539 while (*p != '\n' && *p != ' ' && 540 *p != '\t' && *p != '\0') 541 p++; 542 } else 543 user = p; 544 *p = '\0'; 545 /* 546 * Do +/- and +@/-@ checking. This looks really nasty, 547 * but it matches SunOS's behavior so far as I can tell. 548 */ 549 switch(buf[0]) { 550 case '+': 551 if (!buf[1]) { /* '+' matches all hosts */ 552 hostok = 1; 553 break; 554 } 555 if (buf[1] == '@') /* match a host by netgroup */ 556 hostok = innetgr((char *)&buf[2], 557 (char *)&hname, NULL, ypdomain); 558 else /* match a host by addr */ 559 hostok = __icheckhost(raddr,(char *)&buf[1], 560 af, len); 561 break; 562 case '-': /* reject '-' hosts and all their users */ 563 if (buf[1] == '@') { 564 if (innetgr((char *)&buf[2], 565 (char *)&hname, NULL, ypdomain)) 566 return(-1); 567 } else { 568 if (__icheckhost(raddr,(char *)&buf[1],af,len)) 569 return(-1); 570 } 571 break; 572 default: /* if no '+' or '-', do a simple match */ 573 hostok = __icheckhost(raddr, buf, af, len); 574 break; 575 } 576 switch(*user) { 577 case '+': 578 if (!*(user+1)) { /* '+' matches all users */ 579 userok = 1; 580 break; 581 } 582 if (*(user+1) == '@') /* match a user by netgroup */ 583 userok = innetgr(user+2, NULL, ruser, ypdomain); 584 else /* match a user by direct specification */ 585 userok = !(strcmp(ruser, user+1)); 586 break; 587 case '-': /* if we matched a hostname, */ 588 if (hostok) { /* check for user field rejections */ 589 if (!*(user+1)) 590 return(-1); 591 if (*(user+1) == '@') { 592 if (innetgr(user+2, NULL, 593 ruser, ypdomain)) 594 return(-1); 595 } else { 596 if (!strcmp(ruser, user+1)) 597 return(-1); 598 } 599 } 600 break; 601 default: /* no rejections: try to match the user */ 602 if (hostok) 603 userok = !(strcmp(ruser,*user ? user : luser)); 604 break; 605 } 606 if (hostok && userok) 607 return(0); 608 } 609 return (-1); 610 } 611 612 /* 613 * Returns "true" if match, 0 if no match. 614 */ 615 static int 616 __icheckhost(raddr, lhost, af, len) 617 void *raddr; 618 register char *lhost; 619 int af, len; 620 { 621 register struct hostent *hp; 622 char laddr[BUFSIZ]; /* xxx */ 623 register char **pp; 624 int h_error; 625 int match; 626 627 /* Try for raw ip address first. */ 628 if (inet_pton(af, lhost, laddr) == 1) { 629 if (memcmp(raddr, laddr, len) == 0) 630 return (1); 631 else 632 return (0); 633 } 634 635 /* Better be a hostname. */ 636 if ((hp = getipnodebyname(lhost, af, AI_DEFAULT, &h_error)) == NULL) 637 return (0); 638 639 /* Spin through ip addresses. */ 640 match = 0; 641 for (pp = hp->h_addr_list; *pp; ++pp) 642 if (!bcmp(raddr, *pp, len)) { 643 match = 1; 644 break; 645 } 646 647 freehostent(hp); 648 return (match); 649 } 650